Looking back one, two and five years ago today (give or take) on Worldchanging:

2009The Secret to Low-Water-Use, High-Efficiency Concentrating Solar Power
Concentrating solar thermal power plants (“CSP”) have been identified a number of times in Climate Progress as a core climate solution due to their almost unique potential to replace coal. One of the concerns often cited about CSP is water consumption. In the desert areas where CSP will thrive, the consumption of large amounts of water by conventional wet cooling systems is clearly unsustainable. Dry cooling alternatives will be required. Joe Romm invited Michael Hogan, a long-time power industry executive and currently the Power Programme Director for the European Climate Foundation, to write a piece about a low-water-consuming cooling system...

2008Cities of the Future, Today
As cool as ultra high-performance green buildings are individually, the real action is all with districts. Individual buildings may blaze paths, but if we want to really push the environmental performance of urban areas down to zero-impact levels, we need to think in terms of districts; we need to look at settings where a number of buildings can be built afresh or creatively re-used, and where the infrastructure and public space they share can be recreated in ways no piecemeal agglomeration of individual projects can usually match. Alex Steffen discusses Dockside Green as one example of district design...

2005Tall Green
The success and failure of the human enterprise on this planet will depend on whether, how and how quickly we are able to transform cities to live in harmony with nature's cycles, according to Gil Friend. Here, he looks at recent developments in green skyscraper design...